Billing code 88313: Special stainMedicare rate & RVUs in Guam
Group II histochemical staining highlights tissue features such as fibrosis, iron, or amyloid and is reported once per stain per specimen.
Medicare pays $90.48 for 88313 in the office in Guam (Hawaii, Guam). Which amount applies depends on the service address.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
On this page 9 sections
What 88313 covers
Group II histochemical stains highlight tissue components rather than infectious organisms. Examples include trichrome for fibrosis, Prussian blue for iron, reticulin for tissue architecture, elastic stains for vessel walls, and Congo red for amyloid. Histology staff prepare and stain slides, commonly from paraffin blocks, and a pathologist interprets the findings in the pathology report. These stains may be used on liver biopsies to assess fibrosis or iron, medical kidney biopsies to examine tissue architecture, and cardiac or fat pad biopsies to investigate amyloid.
Report one unit for each distinct Group II stain on each specimen, generally with the applicable tissue examination code, such as 88305 or 88307. The report should identify the specimen, stain, and result. Stains used to identify microorganisms belong in 88312; frozen-section histochemistry and enzyme histochemistry have separate codes. CMS prices the professional interpretation with modifier 26 and the technical preparation, reagents, and staff work with modifier TC. Billing without either modifier represents the global service. Physician work accounts for about 10% of the office total.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
88313 in Hawaii, Guam
| Payment locality | Office | Facility |
|---|---|---|
| Hawaii, Guam | $90.48 | Unavailable |
How the 88313 rate is calculated
Each of 88313’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 88313
RVUs × geographic indexes × conversion factor
Work0.23
0.23 RVUs× 1.000 GPCI
Practice expense2.17
2.17 RVUs× 1.000 GPCI
Malpractice0.02
0.02 RVUs× 1.000 GPCI
Adjusted RVUs
2.4200
Conversion factor
$33.4009
Medicare rate
$80.83
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 88313
The CMS indicators that decide how 88313 is paid alongside other services.
CMS payment indicators · 88313
Special stain
| Rule | CMS value | What it means |
|---|---|---|
| Global period | XXX | The global surgery concept doesn’t apply. |
| Multiple procedures | 0 | No multiple-procedure reduction. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 0 | Not paid without supporting documentation. |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 1 | Diagnostic test with separate professional (26) and technical (TC) components. |
What modifiers do to the payment
Modifier 26 · payment effect
With and without the modifier
88313 without 26 · national office
$80.83
Special stain
88313-26 · Professional component
$11.36
Pays only the interpretation and report.
88313 compared with similar codes
Compare codes · National
5 codes, side by side
How to choose
- 88312Special stain
- Group I is for stains used to identify microorganisms; Group II highlights tissue constituents such as collagen, iron, or amyloid. Select the group by the stain's documented purpose.
- 88342Antibody stain
- 88342 covers an antibody-based immunohistochemical stain. Chemical histochemical stains such as trichrome or iron are reported with 88313; both may be reported when separately performed for distinct diagnostic questions.
- 88314Histochemical stain
- 88314 is an add-on for histochemical staining on frozen sections and is reported with the applicable primary pathology service. Group II stains on routine tissue sections are reported with 88313.
- 88319Enzyme histochemistry
- Stains demonstrating enzyme activity, such as those used in muscle biopsy workups, are reported with 88319 rather than 88313.
88313 billing questions
How many units are reported when several Group II stains are performed?
Report one unit per distinct stain per specimen. A liver biopsy with trichrome and iron stains supports two units; the same stain on two separately submitted specimens also supports two units.
When is 88312 used instead of 88313?
Use 88312 for a stain performed to identify microorganisms, such as a fungal, acid-fast, or Gram stain. Use 88313 for stains demonstrating tissue constituents such as collagen, iron, glycogen, elastic fibers, or amyloid.
Does the stain's purpose matter if the same stain can serve either group?
Yes. A PAS stain used to look for fungi is reported with 88312, while PAS used to evaluate glycogen or basement membranes is reported with 88313.
Is the routine H&E slide separately reportable with 88313?
No. Routine H&E staining is included in the gross and microscopic surgical pathology examination. Report 88313 for a separately performed Group II special stain.
How are modifiers 26 and TC applied?
A pathologist who interprets a slide stained by another entity bills 88313 with modifier 26. The entity providing only slide preparation and staining bills with modifier TC; an entity providing both components bills without either modifier.
What documentation supports each unit?
The pathology report should identify each stain and specimen and describe the result or its diagnostic significance. An order without a reported interpretation does not support billing the professional component.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
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